Why we know so little about phone surveillance

FILE - This Sept. 19, 2007, file photo, shows the National Security Agency building at Fort Meade, Md., during a visit by President Bush. The military intelligence complex an hour outside Washington where the WikiLeaks case goes to court this week is known as a cloak-and-dagger sanctum off-limits to the rest of the world. That reputation is only partly true. In many ways, Marylands Fort Meade is an ordinary Army post, albeit one with a 5,000-acre complex and a golf course. Its also home to the super secure compound of the code-breaking National Security Agency. (AP Photo/Charles Dharapak, file)

Why we know so little about phone surveillance

A copy of a top secret court order leaked to the Guardian newspaper shows that the Obama administration has been collecting phone records of millions of U.S. customers of Verizon since April.The court order will renew debate among privacy advocates and the national security community about surveillance. But if recent history is any guide, it will be a lopsided debate because so little is publicly known.Here's why we know so little.Most investigations are public; terrorism investigations aren't.Under a normal criminal …